The present invention relates to a method for placement of an endosseous implant into an extraction site of a patient.
There has been much research in recent years into handling damaged natural teeth which have been damaged through disease or accident by extracting the teeth and then immediately, or sometimes later, implanting an artificial root which has the same function as the original natural tooth and then attaching a tooth or other prosthetic device to the implanted artificial root.
In the past, various types of artificial teeth and other surgical implants have been developed for replacing teeth or other joints or bone portions. Originally, dental implants and other surgical implants were attached to a patient's bone using various adhesives, mechanically retentive surfaces composed primarily of titanium or titanium dioxide, and later surface coatings of various biologically compatible materials were developed in which the bone grows into and attaches to the implant. Porous materials alone have not always been sufficiently strong for dental implants so that it has been necessary to emplace a piece of solid material, such as metallic center post or rod, inside the porous material to form a surgical implant with a porous surface. Typically, implants and the prosthetic posts that subsequently inserted into implants have been circularly shaped at the point where the implant opens into the oral cavity so that it is possible to drill a circular hole with a conventional drill to precisely fit the cylindrical implant in the bone. Even in the case where new technology involving the use of guided tissue regeneration has been used, a cylindrical implant has been placed into a tooth socket, which is rarely circular at its exit opening. The current technology only delineates that the implant have a sufficiently porous, mechanical, or biological surface to allow the attachment of the bone thereto. A dental implant typically is implanted into bone in the approximate position of an extracted tooth and has a post or other attaching means extending from the top of the implant for attaching an artificial tooth. The inserts are commonly attached with a threaded fastener which threads through the insert into the supporting implant.
The present invention deals with a method of extracting a tooth and then implanting an artificial root and attaching an artificial tooth to the dental implant artificial root or anchoring means. Prior patents that show various types of artificial tooth root implanting and anchoring means may be seen in the Hakamatsuka et al., U.S. Pat. No. 4,713,006, for an artificial tooth root which is divided into a tooth group body and a root holder and in which the material for the artificial tooth root body is selected for its strength. In the Farris et al., U.S. Pat. No. 4,492,577, a surgical implant with a solid interior and porous surfaces is provided and is illustrated with a two-pronged shaped artificial root. In the Niznick U.S. Pat. No. Re. 33,796, a coping insert for use with a dental implant is illustrated in which a thermo-plastic one-piece coping insert is adapted for use with a dental implant anchoring means. In the Hama et al., U.S. Pat. No. 4,818,559, a method for producing endosseous implants is provided which thermally sprays a ceramic material onto the surface of a metallic core for making implants for implantation into the bone for tooth roots and the like. In the Kawahara et al., U.S. Pat. No. 4,964,801, an endosseous implant having a polycapillary structure is provided for being set into the alveolar bone for use in dental prosthesis. In the Flanagan et al. U.S. Pat. No. 4,812,120, an implantable percutaneous device provides for a dental implant which has a metal core that is directly coated with layers of polymer.
In dental implants, various artificial root implants are manufactured in different shapes and materials so that when a tooth is removed from the bone, after the socket is healed, the bone can be drilled for insertion of an artificial root implant which may have a surface to allow the bone to attach thereto and may also be attached or filled with a composition to help the bone adhere to the artificial root implant. In the case where an implant is placed immediately at the time of extraction, the hole is deepened with a cylindrical drill, bone grafting material or guided tissue regeneration membranes are used to cover and surround the top portion of the implant to try to fill the void created by the discrepancy of the cylindrical implant shape in a non-cylindrical hole. The implant is then covered with a gingival flap. The root implant is then allowed to heal so that the bone grows into the porous or specially made surface to anchor the artificial implant to the bone so that at some later period, once the bone has adhered to the artificial root, a prosthetic insert can be attached to the root implant. An artificial tooth, or prosthetic locking attachment can then be attached to the prosthetic insert post with an adhesive or screw type attachment. It is common to attach the prosthetic insert post with a threaded fastener designed to fit a predrilled and threaded bore in the implant. Typically, both the implanted root and the insert have been made with cylindrical shapes so that the bone can be drilled with a cylindrical shape to make an exact fitting artificial root implant match the drilled bore. This has some advantages but makes it easier for the implanted artificial root as well as the insert to rotate or loosen when certain types of pressure are placed on the artificial implant and tooth. It also dictates that the exit shape from the gingiva be circular rather than tooth shaped, thereby adversely affecting the esthetics and manageability of the ultimate prosthetic design.
The present invention utilizes a method and a dental implant which deliberately avoids cylindrical and round shapes in the dental implant as well as in the artificial tooth insert so that when attached to a patient, a greater resistance to the rotation is provided against the breaking loose of the artificial implant by the use of a non-circular shape. It also provides for a more natural exit profile from the gingiva so as to render the implant and prosthetic insert post more acceptable for tooth replacement. Additionally, this invention provides a better design and shape for guided tissue regeneration when implants are placed immediately at the time of extraction of a natural tooth.